1. Field
Example embodiments relate to a digital signal generator which generates a data signal having signal information desired by a user.
2. Description of the Related Art
Generally, devices such as semiconductors are subject to a test process of electric properties after being manufactured to identify whether there is a problem with normal operation of the device. Such a test process is performed by semiconductor test equipment, which tests a semiconductor element using a probe card or a test socket.
Here, a semiconductor to be tested is called a Device Under Test (DUT). Automatic Test Equipment (ATE), mounting test equipment, fixed frequency mounted-type test equipment, etc. are used to test the DUT.
An ATE tests the DUT using a test pattern based on a defect model of a semiconductor IC obtained through previous experimentation. Such an ATE exhibits enhanced performance in detecting a logical failure and/or a parametric error.
Recently, products which are capable of actively varying an operating frequency of a semiconductor element have increased due to demand for low power and long-term use of electronic products, and semiconductor elements which achieve high-speed operation have been developed. Accordingly, semiconductor test equipment used to test defects of semiconductor elements according to a variable-frequency operation is demanded and a high-speed semiconductor test is also demanded.
To meet such requirements, a technique which arbitrarily sets a timing of a final output signal by changing a necessary delay value on a real-time basis using a variable signal delay circuit of a single channel has been developed. Such a variable signal delay circuit uses a Digital Delay Line (DDL) circuit or has a configuration adding a Delay Locked Loop (DLL) circuit to the DDL circuit.
However, since the variable signal delay circuit of a single channel has restrictions on a delay value reset speed thereof, the speed of a final generated timing signal is limited.